*How is yeast growth, as a representative organism in a polluted environment, affected by man-made toxins, such as acidity, heavy metals and petrol?*
...
General facts about yeast (these need to be taken into account for all the experiments- should be kept constant): Optimum temperature at 30 C Optimal pH at 7 10 grams of glucose per every 5 grams of dry yeast (sugar (glucose) is the yeast's food) Measuring the rate of respiration through the amount of Co2 produced (through the use of a gas syringe)
Petrol Experiments: Janneke
Heavy Metal Experiments (copper sulphate): Deyshawn and Ben
Acidity Experiments: Emma
Sherab: petrol and acidity experiment
Petrol Experiment
Aim: to investigate how the amount of petrol, as a pollutant, in the water, affects the growth of yeast, a representative organism in a polluted environment.
List of equipment: - 4590 ml of petrol (3 x (1 + 2 + 3 + 4 + 5) ml) - 1.1.8 L of water (18 x 100ml) - 9090 g of baker’s dry yeast (18 x 5g) - 18180 grams of sugar (18 x 10 g) - a stopwatch - a clamp and stand - a glass syringe - a 5ml pipette, to measure the volume of petrol - a 100ml measuring cylinder, to measure to volume of water - a glass rod, to stir the water and petrol - a spatula, to measure out the mass of yeast - a watch glass - an electric balance - a conical flask with a sidearm - a stopper to close the conical flask
water bath at 30 degree C
Method:
1) collect all materials and set up the clamp and stand with the glass syringe in it, attached to the conical flask
2) using the measuring cylinder, measure out 100ml of water, and pour it into the conical flask. Add 10 grams of sugar.
3) using the pipette, measure out the quantity of petrol used for that experiment and add it to the water in the conical flask (first no petrol at all, then 1ml, then after three trials 2ml, etc)
4) if some petrol was added to the water, use the glass rod to stir and mix the petrol and water a bit
5) put the watch glass on the electric balance, and using the spatula, measure out 5g of baker’s dry yeast
6) reset the stopwatch and make sure the glass syringe is pushed in (so it reads 0ml)
7) drop the yeast in the conical flask, and simultaneously start the stopwatch and put the stopper on the conical flask
8) record every 30 seconds (half a minute) for ten minutes, by reading off the glass syringe, the volume of carbon dioxide gas produced
9) after ten minutes, empty the conical flask
10) repeat the whole experiment (steps 2-9) two more times, so that three trials of exactly the same experiment are recorded in the data table
11) then repeat steps 2-10 for the other experiments each time adding 0ml, then 1ml, 2ml, 3ml, 4ml, and finally 5ml of petrol to the water
12) clean up all materials
2. Heavy Metal Experiments Aim: to investigate how the amount of heavy metal presence, as a pollutant, in the water, affects the growth of yeast, a representative organism in a polluted environment. Three seperate experiments will occur: one with copper powder, one with mercury powder, and one with sodium. List of equipment:
90ml of copper sulphate
1.8 L of water (18 x 100ml)
- 9090 g of baker’s dry yeast (18 x 5g) - 18180 grams of sugar (18 x 10 g) - a stopwatch - a clamp and stand - a glass syringe - a 5ml pipette, to measure the volume of petrol - a 100ml measuring cylinder, to measure to volume of water - a glass rod, to stir the water and petrol - a spatula, to measure out the mass of yeast - a watch glass - an electric balance - a conical flask with a sidearm - a stopper to close the conical flask
water bath at 30 degree C
Rerepeat the above equipment with: --90 ml copper sulphate solution (at 1 molar concentration) (3 x (2 + 4 + 6 + 8 +10) g) Method:
1) collect all materials and set up the clamp and stand with the glass syringe in it, attached to the conical flask
2) using the measuring cylinder, measure out 100ml of water, and pour it into the conical flask. Add the 10 grams of glucose into the water.
3) using the small spoon and balance, measure out the quantity of powder used for that experiment and add it to the water in the conical flask (first no powder at all, then 1g, then after three trials 2g, etc
4) if powder was added to the water, use the glass rod to stir the powder and water together
5) put the watch glass on the electric balance, and using the spatula, measure out 5g of baker’s dry yeast
6) reset the stopwatch and make sure the glass syringe is pushed in (so it reads 0ml)
7) drop the yeast in the conical flask, and simultaneously start the stopwatch and put the stopper on the conical flask
8) record every 30 seconds (half a minute) for ten minutes, by reading off the glass syringe, the volume of carbon dioxide gas produced
9) after ten minutes, empty the conical flask
10) repeat the whole experiment (steps 2-9) two more times, so that three trials of exactly the same experiment are recorded in the data table
11) then repeat steps 2-10 for the other experiments each time adding 0g, then 1g, 2g, 3g, 4g, and finally 5g of heavy metal powder to the water
12) clean up all materials
3. Acidity Experiment Aim: to investigate how varying pH levels, (through the addition of different pH buffers in the water), affects the growth of yeast, a representative organism in a polluted environment.
List of Equipment
-- same equipment as in the other 2 experiments
-- pH buffers of 1, 4, 7, 11, and 14 (to represent common pollutants of sulphuric acid, acid rain, normal, ammonia, and liquid drain cleaner in that order)
Method:
1) collect all materials and set up the clamp and stand with the glass syringe in it, attached to the conical flask
2) using the measuring cylinder, measure out 100ml of water, and pour it into the conical flask. Add 10 grams of sugar.
3) using the pipette, measure out the pH buffer and add it to the water in the conical flask
4) Stir
5) put the watch glass on the electric balance, and using the spatula, measure out 5g of baker’s dry yeast
6) reset the stopwatch and make sure the glass syringe is pushed in (so it reads 0ml)
7) drop the yeast in the conical flask, and simultaneously start the stopwatch and put the stopper on the conical flask
8) record every 30 seconds (half a minute) for ten minutes, by reading off the glass syringe, the volume of carbon dioxide gas produced
9) after ten minutes, empty the conical flask
10) repeat the whole experiment (steps 2-9) two more times, so that three trials of exactly the same experiment are recorded in the data table
11) then repeat steps 2-10 for the other experiments until all pH values have been used
Wednesday 15th: Janneke: we could maybe also do an experiment to see how salinity affects the growth of yeast..... So a slightly edited version can be: "How is the growth of yeast, a representative organism in a polluted environment, affected by man-made pollutants such as acid, ethanol, heavy metals (.....specific ones that will be used in experiment), petrol and salinity?" We just have to find a general way to measure the growth of yeast, and then divide the different experiments (of the different pollutants) between the people in the group, so that each person (or pair) can write the method for one experiment ...... However, all methods are DUE THIS FRIDAY (17th)!!! So we really have to get going on this.......
Thursday 16th: J: ok, so since the methods are due tomorrow, and I havent heard what you guys think n stuff, I will make a rough outline of the petrol experiment (see how that affects yeast growth), which I'll send to Ms. Fletcher or something.... Please tell us (by email or through this wiki) which experiment you would like to work on and so which method you will write..... Maybe we can use the basic outline of the petrol experiment method for all experiments, though, since the basic method for measuring yeast growth can be applied to all experiments I think. So I'll send you all a copy of the petrol experiment when I'm done, to give an idea of how we could maybe carry out the other experiments as well
yeast growth, as a representative organism in a polluted environment, affected
by man-made toxins, such as acidity, heavy metals and petrol?*
...
General facts about yeast (these need to be taken into account for all the experiments- should be kept constant):
Optimum temperature at 30 C
Optimal pH at 7
10 grams of glucose per every 5 grams of dry yeast (sugar (glucose) is the yeast's food)
Measuring the rate of respiration through the amount of Co2 produced (through the use of a gas syringe)
Petrol Experiments: Janneke
Heavy Metal Experiments (copper sulphate): Deyshawn and Ben
Acidity Experiments: Emma
Sherab: petrol and acidity experiment
Aim:
to investigate how the amount of petrol, as a pollutant, in the water, affects the growth of yeast, a representative organism in a polluted environment.
List of equipment:
- 4590 ml of petrol (3 x (1 + 2 + 3 + 4 + 5) ml)
- 1.1.8 L of water (18 x 100ml)
- 9090 g of baker’s dry yeast (18 x 5g)
- 18180 grams of sugar (18 x 10 g)
- a stopwatch
- a clamp and stand
- a glass syringe
- a 5ml pipette, to measure the volume of petrol
- a 100ml measuring cylinder, to measure to volume of water
- a glass rod, to stir the water and petrol
- a spatula, to measure out the mass of yeast
- a watch glass
- an electric balance
- a conical flask with a sidearm
- a stopper to close the conical flask
water bath at 30 degree C
Method:
2.
Heavy Metal Experiments
Aim: to investigate how the amount of heavy metal presence, as a pollutant, in the water, affects the growth of yeast, a representative organism in a polluted environment. Three seperate experiments will occur: one with copper powder, one with mercury powder, and one with sodium.
List of equipment:
90ml of copper sulphate
1.8 L of water (18 x 100ml)
- 9090 g of baker’s dry yeast (18 x 5g)
- 18180 grams of sugar (18 x 10 g)
- a stopwatch
- a clamp and stand
- a glass syringe
- a 5ml pipette, to measure the volume of petrol
- a 100ml measuring cylinder, to measure to volume of water
- a glass rod, to stir the water and petrol
- a spatula, to measure out the mass of yeast
- a watch glass
- an electric balance
- a conical flask with a sidearm
- a stopper to close the conical flask
water bath at 30 degree C
Rerepeat the above equipment with:
--90 ml copper sulphate solution (at 1 molar concentration) (3 x (2 + 4 + 6 + 8 +10) g)
Method:
- 1) collect all materials and set up the clamp and stand with the glass syringe in it, attached to the conical flask
- 2) using the measuring cylinder, measure out 100ml of water, and pour it into the conical flask. Add the 10 grams of glucose into the water.
- 3) using the small spoon and balance, measure out the quantity of powder used for that experiment and add it to the water in the conical flask (first no powder at all, then 1g, then after three trials 2g, etc
- 4) if powder was added to the water, use the glass rod to stir the powder and water together
- 5) put the watch glass on the electric balance, and using the spatula, measure out 5g of baker’s dry yeast
- 6) reset the stopwatch and make sure the glass syringe is pushed in (so it reads 0ml)
- 7) drop the yeast in the conical flask, and simultaneously start the stopwatch and put the stopper on the conical flask
- 8) record every 30 seconds (half a minute) for ten minutes, by reading off the glass syringe, the volume of carbon dioxide gas produced
- 9) after ten minutes, empty the conical flask
- 10) repeat the whole experiment (steps 2-9) two more times, so that three trials of exactly the same experiment are recorded in the data table
- 11) then repeat steps 2-10 for the other experiments each time adding 0g, then 1g, 2g, 3g, 4g, and finally 5g of heavy metal powder to the water
- 12) clean up all materials
3. Acidity ExperimentAim: to investigate how varying pH levels, (through the addition of different pH buffers in the water), affects the growth of yeast, a representative organism in a polluted environment.
List of Equipment
-- same equipment as in the other 2 experiments
-- pH buffers of 1, 4, 7, 11, and 14 (to represent common pollutants of sulphuric acid, acid rain, normal, ammonia, and liquid drain cleaner in that order)
Method:
Good reference for the Heavy Metal Experiment:http://www.uwstout.edu/faculty/ondrusm/manual/pdf/experiment2.pdf
Good reference for pH experiment:http://www.epa.gov/acidrain/education/site_students/phscale.html
Wednesday 15th:
Janneke: we could maybe also do an experiment to see how salinity affects the growth of yeast.....
So a slightly edited version can be: "How is the growth of yeast, a representative organism in a polluted environment, affected by man-made pollutants such as acid, ethanol, heavy metals (.....specific ones that will be used in experiment), petrol and salinity?"
We just have to find a general way to measure the growth of yeast, and then divide the different experiments (of the different pollutants) between the people in the group, so that each person (or pair) can write the method for one experiment ...... However, all methods are DUE THIS FRIDAY (17th)!!! So we really have to get going on this.......
Thursday 16th:
J: ok, so since the methods are due tomorrow, and I havent heard what you guys think n stuff, I will make a rough outline of the petrol experiment (see how that affects yeast growth), which I'll send to Ms. Fletcher or something.... Please tell us (by email or through this wiki) which experiment you would like to work on and so which method you will write..... Maybe we can use the basic outline of the petrol experiment method for all experiments, though, since the basic method for measuring yeast growth can be applied to all experiments I think. So I'll send you all a copy of the petrol experiment when I'm done, to give an idea of how we could maybe carry out the other experiments as well